In configuring automotive vehicles, efficient use of space is an important consideration. This is because various components of automotive vehicles frequently compete for space within the envelope defined by vehicle bodies. The judicious use of space is a consideration not only during assembly of automotive vehicles, but also during maintenance of vehicles. In addition, consuming less space for essential automotive components allows the designer to increase space for optional components and for cabin capacity. While adjusting or decreasing space consumption of one component may not appear to have substantial design effects, cumulative space adjustments and decreased space consumption for several components can result in more efficient use of total space within a vehicle and enhanced design flexibility.
In voltage source inverter arrangements, capacitors are used as energy storage devices providing power buffers to maintain relatively smooth dc link voltages. Typically, capacitance volume accounts for a significant portion of the total volume required by voltage source inverter packaging. Such capacitors are frequently electrolytic or film capacitors. These capacitors are manufactured by winding a thin film to increase the total amount surface area of the film. In the prior art, such capacitors are usually wound tightly around their center to produce enclosed or solid cylinders of different heights and diameters.
In order to reduce loses and EMI, which results from the transmission of power between an electric drive (inverters and capacitors) and an electric motor, it is often desirable to minimize transmission distance between electric drives and motors. In order to minimize distance, the electric drive can be integrated into a common package with a motor. In many hybrid vehicles, the motor(s) are integrated into the mechanical transmission (or gearbox) of the vehicle. Hence, one such embodiment of the system could incorporate the inverter in a container attached externally to the transmission housing so that it is located in close proximity to the electric motor.
A drawback to attaching the electric drive in its enclosed container to the outside of the transmission is the difficulty in packaging the volume of the inverter into the space and form factor allotted. Since the capacitance required by the electric drive comprises a significant volume of the electric drive relocating the capacitance will decrease the volume of the remaining drive components, and thus make the system much simpler to package.